This invention relates to a method for inhibiting crystallization of trimethylolethane from supersaturated aqueous solutions thereof and to the crystallization-inhibited solutions prepared in accordance with that method.
Most commercial customers for industrial chemicals prefer to handle bulk raw materials in liquid form. Liquids can be handled economically in bulk by pumping and metering, thus avoiding the manual labor associated with transporting and opening solid-containing containers and weighing solid charges.
Trimethylolethane is a water soluble crystalline polyhydric alcohol which finds widespread use in the chemical industry particularly in the manufacture of alkyd resins, drying oils and plasticizers. Trimethylolethane (TME), while a crystalline solid in pure form, is for the above reasons advantageously shipped in bulk for commercial usage as its aqueous solutions. Of course, the more concentrated solutions can be made, the more cost efficient shipping and handling can be. Aqueous solutions of TME as concentrated as 80% solids can be shipped as heated solutions in insulated tank trucks. Aqueous solutions of trimethylolethane at 50% solids can be shipped (as solutions) so long as the outdoor temperatures do not drop below 0.degree.-5.degree. C.
The solubility profile of TME in water is such that any cooling of concentrated aqueous TME solutions can easily result in solution supersaturation and concomitant crystallization of TME from solution. Indeed, supersaturated solutions of TME can "crystallize" into a solid crystalline mass. Cooling of concentrated aqueous TME solutions in shipment, in storage tanks and in pumping and metering equipment can result in a plant manager's nightmare. There is little that can be done with the resulting solid crystalline mass once it forms in shipping containers or processing equipment except to find some way to heat the "mass" to again form a high solids aqueous TME solution, or to remove the crystallized material mechanically from the crystal-clogged equipment.
It is therefore an object of this invention to provide a method for inhibiting crystallization in supersaturated aqueous solutions of trimethylolethane.
It is a further object of this invention to provide crystallization-inhibited aqueous trimethylolethane solutions and a method for preparing those crystallization-inhibited solutions.
It is still a further object of this invention to identify materials useful as stabilizers for aqueous trimethylolethane solutions, and to provide a liquid, pumpable grade of aqueous high solids trimethylolethane solution exhibiting resistance to unwanted, premature crystallization of trimethylolethane from solution.